JSFiddle - React, Tailwind, and code Playground

by hicurin

HTML

<input type="text" id="txt" value="203"/>
<select id="revision">
</select>
<input id="btn" type="button" value="Increase" />

JavaScript

var currentIndex = 0;
function createOption(){
    var select = document.getElementById("revision");
    for(var i = 1; i <= 9 ; i++){
        var opt = document.createElement("option");
        opt.value = i;
        opt.innerHTML = i;
        select.appendChild(opt);
    } 
    for(var i = 65; i <= 90; i++){
        var opt = document.createElement("option");
        opt.value = String.fromCharCode(i);
        opt.innerHTML = String.fromCharCode(i);
        select.appendChild(opt);
    }
}
createOption();
document.getElementById("btn").onclick = function(){
    currentIndex ++;
    var txt = document.getElementById("txt");
    var select = document.getElementById("revision");
    var lastChar = txt.value.substr(txt.value.length - 1, 1);
    var firstChar = txt.value.substr(0, 1);
    select.value =  select.childNodes[currentIndex].value;
    txt.value = firstChar + select.childNodes[currentIndex].value + lastChar;
};